This invention relates to a tire lift/carrier assembly or winch unit for raising and lowering and storing a spare tire and wheel assembly and of the general type disclosed in U.S. Pat. Nos. 4,969,630 and No. 5,290,014 which issued to the assignee of the present invention and the disclosures of which are herein incorporated by reference. In the installation and use of such a winch unit, it is sometimes desirable to provide an auxiliary support system which will support the spare tire and wheel assembly in an elevated position under a motor vehicle in the event the winch cable accidentally breaks after an extended period of time and resulting from the cable not being taut. Such a secondary support system is disclosed in U.S. Pat. No. 4,884,785 which issued to the assignee of the present invention and also in U.S. Pat. No. 5,188,341.
If a spare tire winch is not constructed to prevent any backup of the cable and loosening of the spare tire and wheel assembly the winch may not prevent lateral shifting of the tire due to vibration and movement of the vehicle. If the spare tire shifts or vibrates, it is possible that the cable extending from the winch to the spare tire retaining bracket will fray and sever or break adjacent the fitting connected to the tire retaining bracket. If this happens and there is no auxiliary support system as disclosed in the above '785 and '341 patents, the spare tire and wheel assembly are free to drop to the ground while the vehicle is moving on the road. In this event, not only may the spare tire and wheel assembly be lost, but the assembly may result in damage to a trailing vehicle or in causing an accident.